Certain drugs or medicaments (those terms being used interchangeably herein) are preferably provided in powder or dry form (such as a lyophilized form), and require reconstitution prior to administration. Lyophilized drugs, for example, typically are supplied in a freeze-dried form that needs to be mixed with a diluent to reconstitute the substance into a form that is suitable for injection. Medicaments may also be provided in other dry or powder form that require reconstitution.
In addition, drugs may be provided as multipart systems which require mixing prior to administration. For example, one or more liquid (e.g., flowable (slurry or liquid)) components, and/or dry (e.g., powdered or granular) components may be provided in a drug container or delivery device which require mixing prior to administration. The components can be mixed and used to form various administratable drugs, such as insulin.
Prior art devices have been developed that provide a wet component (e.g., liquid) and a dry component (e.g., powder) in separate chambers of a common container with the container being configured to permit the flow of the wet component to the dry component to cause mixing thereof in preparing an administratable solution for injection. U.S. Pat. No. 4,874,381 to Vetter is directed to an injector having a barrel configured for mixing, while U.S. Pat. No. 4,968,299 to Ahlstrand et al. is directed to a drug cartridge having a barrel configured for mixing. Both Vetter et al. and Ahlstrand et al. disclose typical configurations for mixing where a bypass channel is formed in the barrel of the device. As such, the device must be specifically configured for mixing.
Manual force may be applied to a reconstitution device to cause the mixing of the multiple components. In addition, autoreconstitution devices have been developed in the prior art which provide a trigger-activated automated reconstitution. U.S. Pat. No. 6,793,646 to Giambattista et al. is an example of an autoreconstitution device.
In typical reconstitution configurations, it is desired to have the components mixed prior to placing a needle in communication with the reservoir. Thus, with no needle being mounted to the device, the reservoir is not vented during mixing. It has been found that some individuals inadvertently mount a needle onto a device prior to reconstitution. This may result in improper mixing and/or inadvertent wasteful discharge through the needle.
It is noted that autoinjectors are known in the prior art which may also cause reconstitution. Autoinjectors, however, are trigger-activated devices which not only cause reconstitution, but will also cause a needle to pierce a patient's skin with subsequent automated plunger drive causing fluid administration. Autoinjectors typically do not have dose. settings. In addition, the needle is pre-mounted to the device. Examples of this type of device may be found in U.S. Published Patent Application No. 2004/0133163 to Schiffmann and in U.S. Published Patent Application No. 2007/0142769 to Griffiths et al.